Wireless Gigabit is a faster short-range transmission technology, and supports multiple bandwidths. The technology is largely extended from conventional Wi-Fi, and therefore, it may switch to 802.11n. A frequency band corresponding to WiGig is 60 GHz, while a frequency band corresponding to 802.11n is 2.4 GHz. When a user terminal is relatively far away from an access point (AP, Access Point), the user terminal or the AP switches to a frequency band, for example, 2.4 GHz having a lower transmission speed and a longer transmission distance. When the user terminal is relatively near to the AP, the user terminal or the AP switches to the 60 GHz frequency band to obtain a higher connection rate.
The frequency bands are actually not specific frequencies, but frequency ranges, and may vary according to specifications of each country, for example, the 2.4 GHz frequency band refers to a frequency range around 2.4 GHz, and specifically, in China, U.S.A., and Europe, it refers to a frequency range of 2.400-2.4835 GHz, and in Japan, it refers to a frequency range of 2.471-2.497 GHz. A 5 GHz frequency band refers to a frequency range around 5 GHz; and in U.S.A., it refers to 5.85-5.925 GHz, and in Europe, it refers to 5.855-5.925 GHz. A 60 GHz frequency band generally refers to a free spectrum of 56 GHz to 66 GHz, and also varies according to specific situations of each country.
In the foregoing prior art, an encoding mode used to transmit media data is determined according to a standard protocol when the user terminal or the AP accesses a wireless network for the first time, and the encoding mode is no longer changed subsequently even if the user terminal or the AP switches to another wireless network. This method for determining an encoding mode lacks flexibility.